chore(main): release google-apps-chat-v1 0.18.0 (googleapis#32276)

* chore(main): release google-apps-chat-v1 0.18.0

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: release-please[bot]

.release-please-manifest.json

@@ -21,7 +21,7 @@
   "google-analytics-data-v1beta+FILLER": "0.0.0",
   "google-apps-chat": "1.1.2",
   "google-apps-chat+FILLER": "0.0.0",
-  "google-apps-chat-v1": "0.17.0",
+  "google-apps-chat-v1": "0.18.0",
   "google-apps-chat-v1+FILLER": "0.0.0",
   "google-apps-events-subscriptions": "1.1.2",
   "google-apps-events-subscriptions+FILLER": "0.0.0",

google-apps-chat-v1/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+### 0.18.0 (2025-12-16)
+
+#### Features
+
+* Addition of GMAIL_MESSAGE value for RichLinkType enum in the RichLinkMetadata proto ([#32271](https://github.com/googleapis/google-cloud-ruby/issues/32271)) 
+
 ### 0.17.0 (2025-11-21)
 
 #### Features

google-apps-chat-v1/lib/google/apps/chat/v1/version.rb

@@ -21,7 +21,7 @@ module Google
   module Apps
     module Chat
       module V1
-        VERSION = "0.17.0"
+        VERSION = "0.18.0"
       end
     end
   end

google-apps-chat-v1/snippets/snippet_metadata_google.chat.v1.json

@@ -1,7 +1,7 @@
 {
   "client_library": {
     "name": "google-apps-chat-v1",
-    "version": "0.17.0",
+    "version": "0.18.0",
     "language": "RUBY",
     "apis": [
       {